Regular physical activity plays an important role in health and disease prevention. Children and adolescents with intellectual disabilities (ID) have poorer health than other populations and their lack of physical activity may contribute to the health disparities that have been identified in people with disabilities. Evidence supports that children and adolescents with ID do not engage in sufficient physical activity, that their fitness is low, and that they are more sedentary than their typically developing peers. However, research on physical activity in children and adolescents with ID is limited. To inform the development of effective physical activity interventions in adolescents with ID, it is imperative to first examine their activity levels and to understand the factors associated with their participation. Physical activity is known to be influenced by many individual, psychosocial, behavioral, and environmental factors, but the factors are likely to be different in children and adolescents with ID due to their limitations in intellectual functioning and adaptive behaviors, which may limit their opportunities and abilities to participate. The specific aims of this project are: 1) to compare time spent in moderate and vigorous physical activity and in structured activities between adolescents ages 13-18 with ID and typically developing adolescents;2) to compare time spent in sedentary behavior between adolescents with ID and typically developing adolescents;and 3) to compare the individual, family, and community factors associated with physical activity and sedentary behavior between adolescents with ID and typically developing adolescents. Sixty adolescents ages 13-18 with mild ID and 60 typically developing adolescents of comparable chronological age and gender will participate in the study. Physical activity levels will be objectively measured using accelerometers over 7 consecutive days. Through questionnaires and interviews with the adolescent participants and their parents, we will gather information on demographics, adolescent and parent participation in physical activity, barriers and supports to physical activity, the importance that parents and adolescents place on physical activity, and adolescent enjoyment and self-efficacy in relation to physical activity. The health needs of children and adolescents with ID have been under-represented in research efforts, and thus, they represent an under-served minority. The proposed project seeks to address this gap by describing the physical activity patterns of adolescents with ID and comparing them to their typically developing peers. We will also identify the individual, family, and community factors associated with physical activity to determine whether they are different than those found in typically developing adolescents. This information will have direct implications for informing the development of physical activity programs specific to meeting the needs of adolescents with intellectual disabilities. PUBLIC HEALTH RELEVANCE: The US Department of Health and Human Services has identified major heath disparities in children, adolescents, and adults with intellectual disabilities (mental retardation). The poor health of this population may be caused in part by low levels of physical activity, and the government's agenda for improving health includes physical activity promotion. Physical activity is listed prominently as a leading health indicator in Healthy People 2010, and objectives include improving activity levels and reducing sedentary behavior in children. Developing effective health promotion programs for children and adolescents with intellectual disabilities requires an in-depth understanding of their physical activity levels and of the factors uniquely related to behavior.